Wheel support bearing assembly

Abstract

A wheel support bearing assembly includes an outer member, an inner member and double row balls. The inner member includes a hub unit, which has a wheel mounting flange defined in an outer periphery thereof, and an inner ring mounted on the outer periphery of the inboard end of the hub unit. A shoulder is provided in an inner peripheral edge of the inboard end face of the inner ring. A crimped portion, engageable with a stepped face of the shoulder, is provided in the inboard end of the hub unit by diameter expansion. The crimped portion is formed by crimping such diameter expanded portion which is thin walled by providing a hub inner diameter setback in the inner periphery of the inboard end of the hub unit. This thin walled portion is positioned on a side inboardly of the straight line defining a ball contact angle in the inboard raceway surface.

1. A wheel support bearing assembly to be connected with a constant velocity joint, comprising:
 an outer member having an inner periphery formed with double row raceway surfaces; 
 an inner member having an outer periphery formed with raceway surfaces opposed to those raceway surfaces of the respective rows; and 
 double row balls interposed between those opposed raceway surfaces, 
 wherein the inner member is made up of a hub unit, which has a wheel mounting flange defined in an outer periphery of an outboard end thereof and also has a center bore defined in a center portion thereof, and an inner ring mounted on an inner ring mounting area, which is defined in the outer periphery of the inboard end of the hub unit and is so configured as to represent an annular recess, 
 the raceway surfaces of the respective rows are formed in the hub unit and the inner ring; 
 a shoulder is defined to indent in an inner peripheral edge of an inboard end face of the inner ring, 
 a crimped portion, engageable with an axially oriented stepped face of the shoulder in the inner ring, is provided in the inboard end of the hub unit by diameter expansion, 
 the crimped portion of the hub unit is formed by crimping such diameter expanded portion which is thin walled by providing a hub inner diameter setback in the inboard end of the hub unit, and this thin walled portion as a whole is positioned on a side inboardly of the straight line defining a ball contact angle in the inboard raceway surface, and 
 a stem portion of the constant velocity joint is inserted into the center bore of the hub unit and a stepped face is provided in the constant velocity joint so as to orient in the outboard direction, the stepped face being urged against the inboard end face of the inner ring, to thereby constrain the inner member between the constant velocity joint and a nut threadingly mounted on a free end of the stem portion. 
 
     
     
       2. The wheel support bearing assembly as claimed in  claim 1 , wherein the raceway surface in the hub unit is hardened by hardening treatment to provide a hardened surface, and the thin walled portion is a non-hardened portion, the inner ring being hardened in its entirety from surface thereof deep into core thereof by means of a hardening treatment. 
     
     
       3. The wheel support bearing assembly as claimed in  claim 1 , wherein the shoulder in the inner ring has an axial length within the range of 0.25 to 6 mm. 
     
     
       4. The wheel support bearing assembly as claimed in  claim 1 , wherein the shoulder in the inner ring has a radial depth within the range of 0.25 to 2.5 mm. 
     
     
       5. The wheel support bearing assembly as claimed in  claim 1 , wherein the crimped portion of the hub unit has an outer diametric surface held in contact with a straight portion of the shoulder in the inner ring, which has a maximum diameter and is a cylindrical surface. 
     
     
       6. The wheel support bearing assembly as claimed in  claim 1 , wherein the crimped portion of the hub unit has an outer diametric surface held in non-contact with a straight portion of the shoulder in the inner ring, which has a maximum diameter and is a cylindrical surface. 
     
     
       7. The wheel support bearing assembly as claimed in  claim 1 , wherein an inner peripheral surface forming the center bore of the hub unit comprises:
 a general diameter portion which occupies a major portion of the center bore; 
 an intermediate diameter portion defined inboardly of the general diameter portion and having a diameter larger than that of the general diameter portion; and 
 the hub inner diameter setback being defined inboardly of the intermediate diameter portion and having a diameter greater than that of the intermediate diameter portion. 
 
     
     
       8. The wheel support bearing assembly as claimed in  claim 1 , wherein the crimped portion is engaged with the stepped face of the shoulder so as to restrain the inner ring from being moved in an inboard direction during assemblage onto a vehicle.